samedi 13 août 2011

Hubble Offers a Dazzling 'Necklace'











NASA - Hubble Space Telescope patch.

August 13, 2011


The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta (the Arrow). In this composite image, taken on July 2, 2011, Hubble's Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen (green), and nitrogen (red). Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

A giant cosmic necklace glows brightly in this NASA Hubble Space Telescope image.

The object, aptly named the Necklace Nebula, is a recently discovered planetary nebula, the glowing remains of an ordinary, Sun-like star. The nebula consists of a bright ring, measuring 12 trillion miles wide, dotted with dense, bright knots of gas that resemble diamonds in a necklace.

A pair of stars orbiting close together produced the nebula, also called PN G054.2-03.4. About 10,000 years ago one of the aging stars ballooned to the point where it engulfed its companion star. The smaller star continued orbiting inside its larger companion, increasing the giant’s rotation rate.

The bloated companion star spun so fast that a large part of its gaseous envelope expanded into space. Due to centrifugal force, most of the gas escaped along the star’s equator, producing a ring. The embedded bright knots are dense gas clumps in the ring.

The pair is so close, only a few million miles apart, they appear as one bright dot in the center. The stars are furiously whirling around each other, completing an orbit in a little more than a day.

The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta. In this composite image, taken on July 2, Hubble’s Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen (green), and nitrogen (red).

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

Hubble is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy Inc. in Washington.

For images and more information about Hubble, visit:

http://www.nasa.gov/hubble
http://hubblesite.org/news/2011/24

ESA Hubble website: http://www.spacetelescope.org/

Image (mentioned), Text, Credit: NASA / Space Telescope Science Institute, Baltimore, Md. / Donna Weaver / Ray Villard.

Cheers, Orbiter.ch

vendredi 12 août 2011

A Cosmic Exclamation Point











NASA - Chandra X-ray Observatory patch.

August 12, 2011


VV 340, also known as Arp 302, provides a textbook example of colliding galaxies seen in the early stages of their interaction. The edge-on galaxy near the top of the image is VV 340 North and the face-on galaxy at the bottom of the image is VV 340 South. Millions of years later these two spirals will merge -- much like the Milky Way and Andromeda will likely do billions of years from now. Data from NASA's Chandra X-ray Observatory (purple) are shown here along with optical data from the Hubble Space Telescope (red, green, blue). VV 340 is located about 450 million light years from Earth.

Because it is bright in infrared light, VV 340 is classified as a Luminous Infrared Galaxy (LIRG). These observations are part of the Great Observatories All-Sky LIRG Survey (GOALS) combining data from Chandra, Hubble, NASA's Spitzer Space Telescope and Galaxy Evolution Explorer (GALEX) and ground-based telescopes. The survey includes over two hundred LIRGs in the local Universe. A chief motivation of this study is to understand why LIRGs emit so much infrared radiation. These galaxies generate energy at a rate this is tens to hundreds of times larger than that emitted by a typical galaxy. An actively growing supermassive black hole or an intense burst of star formation is often invoked as the most likely source of the energy.

Work on the full GOALS survey is ongoing, but preliminary analysis of data for VV 340 provides a good demonstration of the power of observing with multiple observatories. The Chandra data show that the center of VV 340 North likely contains a rapidly growing supermassive black hole that is heavily obscured by dust and gas. The infared emission of the galaxy pair, as observed by Spitzer, is dominated by VV 340 North, and also provides evidence for a growing supermassive black hole. However, only a small fraction of the infrared emission is generated by this black hole.

By contrast most of the ultraviolet and short wavelength optical emission in the galaxy pair -- as observed by GALEX and HST -- comes from VV 340 South. This shows that VV 340 South contains a much higher level of star formation. (The Spitzer and GALEX images are not shown here because they strongly overlap with the optical and X-ray images, but they are shown in a separate composite image.) VV 340 appears to be an excellent example of a pair of interacting galaxies evolving at different rates.

These results on VV 340 were published in the June 2009 issue of the Publications of the Astronomical Society of the Pacific. The lead author was Lee Armus from the Spitzer Science Center in Pasadena, CA.

Read more/access all images: http://chandra.harvard.edu/photo/2011/vv340/

Image, Text, Credit: X-ray NASA / CXC / IfA / D.Sanders et al; Optical NASA / STScI / NRAO / A.Evans et al.

Greetings, Orbiter.ch

jeudi 11 août 2011

Cosmic Inkblot Test








NASA - SPITZER Space Telescope logo.

August 11, 2011


The Dumbbell Nebula, also known as Messier 27, pumps out infrared light in this image from NASA's Spitzer Space Telescope. The nebula was named after its resemblance to a dumbbell when seen in visible light. It was discovered in 1764 by Charles Messier, who included it as the 27th member of his famous catalog of nebulous objects. Although he did not know it at the time, this was the first in a class of objects, now known as planetary nebulae, to make it into the catalog.

Planetary nebulae, historically named for their resemblance to gas-giant planets, are now known to be the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers, which are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible-light colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years.

Image, Text, Credits: NASA / JPL-Caltech / Harvard-Smithsonian CfA.

Greetings, Orbiter.ch

mercredi 10 août 2011

A Spiral in Leo












ESO - European Southern Observatory logo.

10 August 2011

 A spiral galaxy in Leo

This new picture from ESO’s Very Large Telescope shows NGC 3521, a spiral galaxy located about 35 million light years away in the constellation of Leo (The Lion). Spanning about 50 000 light-years, this spectacular object has a bright and compact nucleus, surrounded by richly detailed spiral structure.

The most distinctive features of the bright galaxy NGC 3521 are its long spiral arms that are dotted with star-forming regions and interspersed with veins of dust. The arms are rather irregular and patchy, making NGC 3521 a typical example of a flocculent spiral galaxy. These galaxies have “fluffy” spiral arms that contrast with the sweeping arms of grand-design spirals such as the famous Whirlpool galaxy or M 51, discovered by Charles Messier.

The spiral galaxy NGC 3521 in the constellation of Leo

NGC 3521 is bright and relatively close-by, and can easily be seen with a small telescope such as the one used by Messier to catalogue a series of hazy and comet-like objects in the 1700s. Strangely, the French astronomer seems to have missed this flocculent spiral even though he identified several other galaxies of similar brightness in the constellation of Leo.

It was only in the year that Messier published the final version of his catalogue, 1784, that another famous astronomer, William Herschel, discovered NGC 3521 early on in his more detailed surveys of the northern skies.  Through his larger, 47-cm aperture, telescope, Herschel saw a “bright center surrounded by nebulosity,” according to his observation notes.

In this new VLT picture, colourful, yet ill defined, spiral arms replace Herschel’s “nebulosity”. Older stars dominate the reddish area in the centre while young, hot blue stars permeate the arms further away from the core.

Wide-field view of the sky around NGC 3521

Oleg Maliy, who participated ESO’s Hidden Treasures 2010 competition [1], selected the data from the FORS1 instrument on ESO’s VLT at the Paranal Observatory in Chile that were used to create this dramatic image. Exposures taken through three different filters that passed blue light (coloured blue), yellow/green light (coloured green), and near-infrared light (coloured red) have been combined to make this picture. The total exposure times were 300 seconds per filter. Oleg’s image of NGC 3521 was a highly ranked entry in the competition, which attracted almost 100 entries.

Notes:

[1] ESO’s Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO’s vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. To find out more about Hidden Treasures, visit http://www.eso.org/public/outreach/hiddentreasures/.

More information:

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Link:

    Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Images, Text, Credits: ESO / O. Maliy / IAU and Sky & Telescope / Digitized Sky Survey 2.

Greetings, Orbiter.ch

mardi 9 août 2011

Solar Flares: What Does It Take to Be X-Class?












NASA logo / NOAA logo labeled.

August 10, 2011


Video above: Solar flares are classified according to their strength. The smallest ones are A-class, followed by B, C, M and X, the largest. Credit: NASA / Goddard / S. Wiessinger.

Solar flares are giant explosions on the sun that send energy, light and high speed particles into space. These flares are often associated with solar magnetic storms known as coronal mass ejections (CMEs). The number of solar flares increases approximately every 11 years, and the sun is currently moving towards another solar maximum, likely in 2013. That means more flares will be coming, some small and some big enough to send their radiation all the way to Earth.

The biggest flares are known as "X-class flares" based on a classification system that divides solar flares according to their strength. The smallest ones are A-class (near background levels), followed by B, C, M and X. Similar to the Richter scale for earthquakes, each letter represents a 10-fold increase in energy output. So an X is ten times an M and 100 times a C. Within each letter class there is a finer scale from 1 to 9.

C-class and smaller flares are too weak to noticeably affect Earth. M-class flares can cause brief radio blackouts at the poles and minor radiation storms that might endanger astronauts.

And then come the X-class flares. Although X is the last letter, there are flares more than 10 times the power of an X1, so X-class flares can go higher than 9. The most powerful flare measured with modern methods was in 2003, during the last solar maximum, and it was so powerful that it overloaded the sensors measuring it. The sensors cut out at X28.


The Solar and Heliospheric Observatory (SOHO) spacecraft captured this image of a solar flare as it erupted from the sun early on Tuesday, October 28, 2003. Credit: NASA / SOHO.

The biggest X-class flares are by far the largest explosions in the solar system and are awesome to watch. Loops tens of times the size of Earth leap up off the sun's surface when the sun's magnetic fields cross over each other and reconnect. In the biggest events, this reconnection process can produce as much energy as a billion hydrogen bombs.

If they're directed at Earth, such flares and associated CMEs can create long lasting radiation storms that can harm satellites, communications systems, and even ground-based technologies and power grids. X-class flares on December 5 and December 6, 2006, for example, triggered a CME that interfered with GPS signals being sent to ground-based receivers.


The Halloween solar storms of 2003 resulted in this aurora visible in Mt. Airy, Maryland. Credit: NASA / George Varros.

NASA and NOAA – as well as the US Air Force Weather Agency (AFWA) and others -- keep a constant watch on the sun to monitor for X-class flares and their associated magnetic storms. With advance warning many satellites and spacecraft can be protected from the worst effects.

Related Links:

    › Recent Solar Events: http://www.nasa.gov/mission_pages/sunearth/multimedia/Solar-Events.html

    › Space Weather Frequently Asked Questions: http://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html

    › View video of 2003 Halloween Solar Storm: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=17956765

Images (mentioned), Video (mentioned), Text, Credit: NASA's Goddard Space Flight Center, Karen C. Fox.

Cheers, Orbiter.ch

NASA Mars Rover Approaches Long-Term Goal











NASA - Mars Rover Exploration "Opportunity" (MER-B) patch.

August 10, 2011


NASA's Mars Exploration Rover Opportunity used its panoramic camera to capture this view of a portion of Endeavour crater's rim. NASA's Mars Exploration Rover Opportunity used its panoramic camera (Pancam) to capture this view of a portion of Endeavour crater's rim after a drive during the rover's 2,676th Martian day, or sol, of working on Mars (Aug. 4, 2011). Image Credit: NASA / JPL-Caltech / Cornell / ASU.

The NASA Mars rover Opportunity has gained a view of Endeavour crater from barely more than a football-field's distance away from the rim. The rim of Endeavour has been the mission's long-term goal since mid-2008.

Endeavour offers the setting for plenty of productive work by Opportunity. The crater is 14 miles (22 kilometers) in diameter -- more than 25 times wider than Victoria crater, an earlier stop that Opportunity examined for two years. Observations by orbiting spacecraft indicate that the ridges along Endeavour's western rim expose rock outcrops older than any Opportunity has seen so far. The selected location for arrival at the rim, "Spirit Point," is at the southern tip of one of those ridges, "Cape York," on the western side of Endeavour.

Mars Rover Exploration Opportunity. Image Credit: NASA / JPL-Caltech
 
Opportunity and Spirit completed their three-month prime missions on Mars in April 2004. Both rovers continued for years of bonus, extended missions. Both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. The mission of the Spirit rover, for which Spirit Point was named, was concluded in May, 2011, after the rover did not re-establish communications following the Martian winter.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington. More information about the rovers is online at: http://www.nasa.gov/rovers

Images (mentioned), Text, Credit: NASA / JPL / Guy Webster.
 
Greetings, Orbiter.ch

CERN experiment weighs antimatter with unprecedented accuracy












CERN - European Organization for Nuclear Research logo.

August 10,2011

In a paper published 28 July 2011 in the journal Nature, the Japanese-European ASACUSA experiment at CERN reported a new measurement of the antiproton’s mass accurate to about one part in a billion. Precision measurements of the antiproton mass provide an important way to investigate nature’s apparent preference for matter over antimatter.

The ASACUSA experiment

“This is a very satisfying result,” said Masaki Hori, a project leader in the ASACUSA collaboration. “It means that our measurement of the antiproton’s mass relative to the electron is now almost as accurate as that of the proton.”

Ordinary protons constitute about half of the world around us, ourselves included. With so many protons around it would be natural to assume that the proton mass should be measurable to greater accuracy than that of antiprotons. After today’s result, this remains true but only just. In future experiments, ASACUSA expects to improve the accuracy of the antiproton mass measurement to far better than that for the proton. Any difference between the mass of protons and antiprotons would be a signal for new physics, indicating that the laws of nature could be different for matter and antimatter.


Image above: The ASACUSA experiment at CERN's AD antiproton decelerator catches antiprotons in helium, where the antiprotons replace electrons, giving exotics atoms.

To make these measurements antiprotons are first trapped inside helium atoms, where they can be ‘tickled’ with a laser beam. The laser frequency is then tuned until it causes the antiprotons to make a quantum jump within the atoms, and from this frequency the antiproton mass can be calculated.  However, an important source of imprecision comes from the fact that the atoms jiggle around, so that those moving towards and away from the beam experience slightly different frequencies. 

ASACUSA experiment

A similar effect is what causes the siren of an approaching ambulance to apparently change pitch as it passes you in the street. In their previous measurement in 2006, the ASACUSA team used just one laser beam, and the achievable accuracy was dominated by this effect. This time they used two beams moving in opposite directions, with the result that the jiggle for the two beams partly cancelled out, resulting in a four times better accuracy.

ASACUSA Experiment - Antiprotons weighed with unprecedented precision

“Imagine measuring the weight of the Eiffel tower” said Hori. “The accuracy we’ve achieved here is roughly equivalent to making that measurement to within less than the weight of a sparrow perched on top. Next time it will be a feather.”

Further information:

Video: CERN News ASACUSA Experiment: http://cdsweb.cern.ch/record/1371017

Follow CERN at:

    http://www.cern.ch
    http://twitter.com/cern/
    http://www.youtube.com/user/CERNTV
    http://www.quantumdiaries.org/

Note:

1. CERN, the European Organization for Nuclear Research, is the world's leading laboratory for particle physics. It has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a candidate for accession. India, Israel, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.

Images, Video, Text, Credit: CERN.

Best regards, Orbiter.ch